Scanning device



c. F. JENKINS SCANNING DEVICE Oct. 27, 1931.

Filed May 2, 1929 Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNORTO JENKINS LABORATORIES, OF "WASHINGTON, DISTRICT OF COLUMBIA, A CORPORA- TION OF THE DISTRICT OF COLUIVIBIA I SCANNING DEVICE scanning-disc motor J.

The film is in constant movement, and the disc rotates at such as Will-{MISS the desired number of scanning apertures across each film picture-frame, as, for example, a LS-line per-frame scanning.

In operation, the light having, been turned on, the motor is started. The motor rotates the scanning disc and also draws the film E down across the light beam; and the lens D projects the film picture-frames to the forwardfocal plane, which is the plane in which the scanning disc A rotates. The image light passing through the scanningapertures is directed by lens C onto the lightsensitivecell B.

The general principles involved are so well known to those skilled in this art, that detailed description is probably not required. The invention consists of the new location of the'elements to produce a result far superior and more dependable than any other arrangement of like parts heretofore employed y applicant.

. he surprising improvement in the quality of the picture resulting from the new locaform image-current translation.

In the use of a disc scanner which scans the film picture frames directly, the film must lie so very close to the film, with apertures-in the disc so small for good detail of each three-quarter inch film frame, that two serious diificulties are immediately encountered; i. e., (1) diffraction blurs the sharpness of the scanning; and the necessary proximity of the disc to the film soon fills up the scanning apertures, so that the translation of picture-image into electrical tion, the scanning disc are larger, so that diffraction bears a lesser relation to the aperture area; (2) the disc lies in a free air, removed from the proximity of the film, and, therefore, does not clog up with dirt and/or oil; and (3) the apertures may be made square increasing the li ht ffi i I t on of the elements of the system comes VVjth th d th bj t i View th about from the increased latitude of scaninvention consists of the novel combination g aperture shape and of parts herein described, illustrated in the Y always y free of foullng accumuladrawings, and particularly pointed out in the claims.

In the drawings, Figure 1 is a diagrammatic illustration of the mechanism, and Figure 2 a plan view of the scanning disc.

In the drawings, A is the scanning disc, having a series of circularly arranged scanning apertures A2 therein, only a portion of the whole of which are shown. B is a sensitive cell; C a lens for directing the diverging-paths (of the light beam) into the cell. is a projecting lens for enlarging and fill up the apertures with dirt, close enough to gather oil.

Also the projected image, in the arrangement of this application, is large enough to in the scanning disc, obviously an advantage of a third increase inlight falling on the cell therethrough.

n a scanning disc Where the indivdual apertures are but one-two thousand three hundred and fourth part of the three-quarter E plctllrefwimes by prOlePt1n t0 inch square picture on a motion picture the focal Pl 1n Yh the scalmmg dlsc film, the apertures are so small that, even if rotates- F 18 an auxlhary lens Whlch y p it were possible to make them square, diffraclllity IlOt be found ddViLlltitgQOllS t0 USO. tion vould make them appear round.

a light-source and its light-concentrating deiflraction is a factor of the boundary vices. H is the geared film-sprocket and edge of the aperture, while the light falling revolutions-per-minute.

ermit the em lo ment of s uare apertures 1 L assembly, driven by the I on the cell is a factor of the square of the diameter; it will readily be seen, therefore, that enlarging the aperture increases the advantages 0 direct light much faster than the disadvantages of diffraction loss.

Not only is this true, but the location of the sensitive cell close beyond the scanning disc, with the picture image directed onto the disc by a lens, the cell is effected by both the directed light and the diffracted light, obviousl a marked gain in cell activity.

While the percentage of gain in this system over the old system has not yet been measured, the actual gain results in a great improvement in the received picture, increasing the black of the blacks in the picture and the sharpness of the image. I

What I claim, is

1. In combination a light source, a motion icture film, a scanning disc having a series of square scanning openings, means for proiecting a magnified image of each picture frame openings in said disc being enlarged in proportion to the magnification of said image.

2. In combination a'motion picture film, a scanning disc having a series of enlarged square perforations, said disc having a scanning field a plurality of times as large as a motion picture frame, and means for projecting upon said disc an image of the picture frames of substantially the same size as the scanning field of said disc.

i said 3. In combination means for producing a magnified image of a subject to be scanned, and means for scanning said magnified image including a perforated disc having square perforations enlarged in proportion to the said magnification.

4. In a scanning system of the type wherein a subject is scanned in successive areas of elemental size, the method which comprises projecting on the plane of the scanner an en larged image of the subject, the openings in scanner being enlarged in proportion to the magnification of the image, optically collecting both the directed and diffracted light passing through the scanner, and trans lating said collected light into corresponding photo-electric currents.

In testimony whereof I gnature CHARLES have affixed my FRANCIS JENKINS.

on the scanning field of said disc, the 

